The present invention relates to a multipurpose folding tool, and particularly to such a tool including folding scissors, a blade latch release mechanism, and handles that provide comfort during use of pliers incorporated in such a tool.
As shown in Leatherman U.S. Pat. No. 4,238,862, Rivera U.S. Pat. No. 5,743,582 and Berg, et al., U.S. Pat. No. 5,745,997, multipurpose folding tools are well known and may contain folding pliers, various folding tool bits such as screwdrivers, files, and knife blades, and folding scissors that can be stored in cavities defined within handles configured as generally U-shaped channels. Tools of this type may include latches that hold a selected one of various screwdrivers or blades in an extended, operational position with respect to one of the handles, as shown in U.S. Pat. No. 5,979,059. Such tools may incorporate numerous types of handles, folding and latching arrangements, and folding scissors.
As useful as such folding multipurpose tools are, they still leave improvement desirable in certain details of their construction and operation. In particular, releasing certain latch mechanisms that hold selected blades in an extended position may require another blade or tool to be opened, or may entail use of a latch release lever that is located within a tool handle, occupying space that would better be occupied by a useful tool bit or blade. Accordingly, an improved latch release mechanism is desired. Preferably, such a latch release mechanism should be able to be operated easily, without the tool having to be held in a particular way in order to release a latched blade.
While functional blade latch mechanisms have previously been known in folding tools whose handles are of sheet metal construction, greater security for keeping a selected blade latch in an extended position is desired.
Most folding multipurpose tools having handles in the form of U-shaped channels have the open sides of the channels facing outwardly away from each other when the handles are unfolded to use a pair of pliers or similar tool jaws, in order to be able to receive the tool jaws within the channels when such a tool is folded. The channel sides, however, often have narrow edges that make use of such pliers uncomfortable. It is therefore desired to provide comfortable surfaces to be gripped when a multipurpose tool with handles in the form of channels is unfolded to permit use of the incorporated pliers or similar tools.
Construction of a folding multipurpose tool has previously required costly adherence to close manufacturing tolerances. Assembly of the pivot joint interconnecting a folding tool handle with a pliers jaw or the like has required adjustment by skilled personnel for the handles to be held securely in either an extended configuration or a folded condition with respect to a pair of tool jaws, yet also be folded and unfolded easily. It is therefore desired to provide a mechanism that permits smoothly folding and unfolding the handles, that operates reliably to hold the handles in a selected position with respect to such pliers jaws or the like, and that is less costly than the previously known corresponding mechanisms.
It is sometimes difficult to cut certain fibrous cords or bundles of strong fibers with scissors small enough for stowage in a folding multipurpose tool""s handles. Small, tough fibers are sometimes squeezed out from between the scissors blades, and it is therefore desired to provide easily used folding scissors that overcome that problem.
Folding multipurpose tools have previously incorporated container openers intended to remove crown caps from bottles, to pierce the tops of beverage cans, and to remove the tops from cans used to preserve foods and the like. Such previously available openers have either been undesirably large, or if small enough to fit well within the space available in a folding multipurpose tool, such openers have tended not to function well in removing the tops from cans, often leaving rough or burred edges. It is therefore desired to provide a combination opener that performs well and reliably, without leaving excessively burred edges, yet is easily and inexpensively manufactured.
In using screwdrivers included in a folding multipurpose tool twisting forces may cause the handles of previously available tools to move undesirably with respect to each other. Also, where several blades may be stowed in a handle it is often difficult to open blades located between others. Tool construction that will keep a pair of handles securely located as they should be with respect to each other during use of such screwdriver blades, and that will also facilitate opening of a folded blade is therefore desired.
What is desired, then, is an improved multipurpose folding tool including improvements in some or all of the above-mentioned areas.
The present invention provides answers to the needs mentioned above for improvements in various aspects of a folding multipurpose tool. In particular, in accordance with one aspect of the present invention, a blade latch release mechanism includes a latch release lever located within a channel-shaped handle for a multipurpose tool, adjacent one side of the handle. The latch release lever includes a protruding part which is moved to press against a latch spring and thus remove a catch from a notch defined in the base of a folding blade or tool bit.
In one preferred embodiment of a latch release mechanism according to the present invention a latch operating lever provides a force-multiplying mechanical advantage to move a cam arranged to move a latch release lever.
In one preferred embodiment of such a latch release mechanism an arcuate grip surface is located so as to provide an increasing lever arm length at the position where a person""s thumb or finger is most likely to contact the grip surface during movement of the latch release operating lever, so that the mechanical advantage available to the user increases as the mechanism moves the latch spring further, and the force required to continue to move the latch release operating lever in releasing latch increases only slightly throughout the entire length through which the latch release operating lever has to be moved.
According to another aspect of the invention, the sides of the channel-shaped handle include rims merging with an outer surface of the handle in a smoothly arcuate surface. Such rims extend inwardly within the handle, defining a space for a portion of a latch release lever.
As another principal aspect of the present invention, the rim along the margin of each sidewall of the channel-shaped handle continues without interruption from one end of the handle to an opposite blade pivot end of the handle, providing a smooth, comfortable surface to be gripped, even in the areas where the margin of the sidewall is indented to give access to blades or tool bits stowed within cavities defined by the handles.
In one embodiment of this aspect of the invention the rim extends inwardly far enough to engage the back of a blade adjacent the sidewall of the handle to keep such a blade stowed within the handle while other blades located closer to the center of the handle are raised from their stowed positions.
According to another major aspect of the invention, a spring is attached to the handle and rides on a cam surface on a tang of a pliers jaw to control pivoting motion of each handle with respect to the tangs of a pair of pliers jaws and, by camming action, to urge the handles into the fully extended position or into a folded position with respect to the pliers jaws once the handles approach such a position with respect to the tangs of the pliers jaws.
In one embodiment of this aspect of the invention, a raised portion of the tang of a pliers jaw cooperates with a lateral surface on the spring to keep the spring aligned properly with the tang.
In such an embodiment of this aspect of the invention, the spring may have a forked outer end including a pair of prongs located on opposite sides of a centrally located raised portion of the tang of a pliers jaw.
In another embodiment of this aspect of the invention an interference bump is provided on the raised portion of the tang of a pliers jaw to engage an interior surface of the channel-shaped handle at the same time the spring acts in a cam-following manner on the cam surface of the pliers jaws to hold a handle securely in a fully extended position with respect to the tang of a pliers jaw.
Another aspect of the present invention is the provision of a folding scissors whose blades include edges that are straight except for a serrated portion on either or both of the blades near their outer tips.
In one preferred embodiment of the folding scissors aspect of the present invention, a spring extends alongside a base portion of one of the legs of the scissors and engages the other leg of the scissors to return the scissors blades to an open position after a cutting stroke of the scissors. In a preferred embodiment of this aspect of the invention, the spring extends from a base which is coupled to the first scissors leg with some freedom to pivot to provide clearance to permit the scissors to be folded and stowed within a cavity defined within one of the handles, with the spring relaxed when the scissors are stowed. In a preferred embodiment of the invention, the spring extends generally in the shape of a xe2x80x9cUxe2x80x9d, providing ample length to avoid excessive stress.
According to another aspect of the present invention a container opener includes a hook with a throat area behind the tip of the hook to provide clearance for a crimped rim of a container such as a xe2x80x9ctinxe2x80x9d can, and a sharp edge on the front part of the opener faces back toward the tip of the hook to cut free the top of such a container efficiently.
As yet another aspect of the present invention, interlocking portions of folded blades stowed within the cavities defined by the handles of the tool extend closely alongside each other, between such interlocks and other blades or tool bits stowed within the opposite handles, preventing the handles from moving laterally with respect to each other when the handles are folded together about the associated pliers jaws or the like.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.